The behaviour of editable links is controlled by the user default WebKitEditableLinkBehavior. This can be set via a private WebPreference. If the preference is OnlyLiveWithShiftKey, then the link will only be active when the shift key is pressed (WinIE/Firefox behaviour). If the preference is WebKitEditableLinkAlwaysLive or WebKitEditableLinkDefaultBehavior, then the link is always active (Safari 2.0 behaviour). Finally, if the preference is WebKitEditableLinkLiveWhenNotFocused, the link will only be live if the selection before clicking on the link is not in the same editable block as the link.

Also, when a link is 'live' it can be dragged as a link, and when the link isn't 'live', dragging a link just performs a normal text selection.